1. Field of the Invention
The invention relates to polymeric bleach precursors which are non-sensitizing to the skin.
2. The Related Art
Active oxygen-releasing materials are normally only able to effect removal of stain and soil from substrates at relatively high temperatures. The art has partially solved the temperature problem through the use of activators. These activators, also known as bleach precursors, often appear in the form of carboxylic acid esters or amides. In an aqueous liquor, hydroperoxide anions generated from hydrogen peroxide react with the ester or amide to generate a corresponding peroxyacid. Commercial application of this technology is found in certain fabric bleaching detergent powders incorporating tetraacetylethylenediamine (TAED) and sodium nonanoyloxybenzene sulfonate (SNOBS).
Great care must be exercised in the manufacturing process to avoid contact with precursors because of potential skin sensitization. This medical condition is particularly evident with sulfophenyl esters because a highly efficient leaving group, the sulfophenyl moiety, is generated which through its reactivity causes sensitization. It has been speculated that the precursors penetrate the skin and react with proteins in the body to give an acylated protein. These acylated proteins likely stimulate a T-cell response resulting in irritancy and/or skin sensitization. The problem is particularly acute in the manufacturing process wherein workers are potentially exposed to high levels of the precursor.
Accordingly, it is an object of the present invention to provide a bleaching system and a precursor for such system exhibiting little or no skin sensitization.
A further object of the present invention is to provide a bleaching system and precursors of improved efficacy in removing stains from substrates.
Still a further object of the present invention is to provide a method for bleaching stained substrates such as clothes, household hard surfaces including sinks, toilets and the like, and even dentures, with a precursor of relatively low skin sensitization capability.
Other objects of the present invention will become apparent through the following summary, detailed description and examples.